Pong v2.0

We'll be making the following additions to the PONG CODE we began yesterday. We'll be spending a few days on this.

1. Keep track of the current score.
   
2. Keep track of the current number of times the ball has hit the paddle; reset this number when somebody wins.
   
3. There should be a sound played when the ball strikes a paddle.
   
4. There should be a different sound played when the ball strikes a wall.
   
5. The paddles should be replaced by similarly sized bitmap images.
   
6. The ball should be replaced with a similarly sized bitmap image.
   
7. The rest time in the main logic loop should get shorter as the number of hits increases.

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